Portable panel punch



Feb. 10, 1970' Boscg ETAL 3,494,033

PORTABLE PANEL PUNCH Filed Jan. 26, 1968 2 Sheds-Sheet 1 Fig. l

INVENTORS. Andrew J. Bqwo BY Denny L. Em/g wewmjm THE/R ATTORNEYS Feb;10, 1970 A. J. Bosco ET AL 3,494,033

PORTABLE PA-NEL PUNCH Filed Jan. 26, 1968 2 Sheets-Sheet z k STEP'CISTEP d 4o F/g 5 1 P C Andrew $2 23? BY Denny L. Emig [/44 0a,, Mia/aTHE/R ATTORNEYS United States Patent 3,494,033 PORTABLE PANEL PUNCHAndrew J. Bosco, RED. 4, Meadville, Pa. 16335, and Denny L. Emig,Meadville, Pa.; said Emig assignor to said Bosco Filed Jan. 26, 19 68,Ser. No. 700,964 Int. Cl. B26f N00 US. Cl. 30-360 9 Claims ABSTRACT OFTHE DISCLOSURE A tool for punching an opening in a panel by closing apunch member against the panel to be cut, applying sufficient force topull the punch member through the panel and into a die member having acutting opening corresponding to a cutting face of the punch member. Thepunch member is removeably secured in a base member, and the cuttingopening of the die member into which the punch member travels duringoperation of the punch is formed by inserts releaseably secured in thedie member.

This invention relates to punching tools and specifically to a portabletool for use in punching a panel to provide an opening therein ofdesired configuration.

Our invention is useful in forming panel openings for electrical lightswitches. More particularly, our punch is useful for making rectangularopenings in industrial electrical switch boxes for mounting one or aplurality of control switches. It is in the latter application where theadvantages of our new punch are most apparent.

Industrial plant electricians carry what is known as a belt whichcontains a large number of tools including pliers, wire cutters,strippers, etc., all used in the trade. The bulk and weight of the belt(often exceeding 20 pounds) make a physical demand on its wearer; hence,any tool proposed for addition to the belt must not only have strengthand utility, but be both light and compact.

Additionally, a useful tool must be suitable for extended periods oftime without maintenance, efficient and as safe as possible to operate,and repairable with a minimum expense. Our punch meets all theserequirements.

Present panel punches have several drawbacks. Most metal punches are notportable in that they require a separate bed or are useful only with astationary press. Many are operable by striking the punch with a mallet.Those which can be carried to the job site require the use of an anvilto stabilize the workpiece and absorb the force of a mallet blow.Several types exhaust the punched blank from the punch. These areunsuitable for usev in and around electrical switch boxes which containexposed electrical current carrying switches, relays and cable leads.Finally, none can be sharpened, repaired or renewed easily, if at all,and most are discarded when the punch member or cutting edges wear, at ahigh replacement cost.

Basically, our novel punch comprises a die member and a punch memberwhich are adapted to close together against a panel of sheet metal,plastic or other material to be punched. In this connection, the wordpanel is used to define any workpiece which is thin in at least onedimension such as sheet or strip. The die member carries inserts whichform cutting edges with which a punch member, carried by a base member,engages to punch a panel between them. The die member and the basemember are aligned by means of pins which extend from the base member,through holes formed in the panel, and into the cutting insert of thedie member. A bolt carrying a tension absorbing thrust bearing extendsthrough the die member and a hole in the panel, suitably drilled for thepurpose, and is threaded into the punch member.

A feature of the punch is a template, first useful for drilling in thepanel the necessary holes for the aligning pins and bolt, and which maybe next useful for determining the maximum thickness of metal which canbe cut by our punch, as will be explained hereinafter. When the die andbase members are properly aligned, one on either side of the panel, thebolt is threaded into the punch member and torqued to close the die andbase members to force the punch through the panel, past the cuttingedges to form the desired opening.

The blank punched remains on the bolt and within the insert-carrying diemember and, in the case of an electrical circuit box, outside the boxand away from hot wires. The base member inside the box is retained inthe panel by the punch member and the aligning pins until it isphysically removed, avoiding contact with any of the electrical circuitsin the box.

One or a number of punches can be manufactured easily and economicallysince all closely toleranced openings in the punch are formed bydrilling or milling and none need be hand filed or broached.

Having described our invention broadly, details of its structure,operation, and utility will become apparent from the followingdescription and the accompanying drawings in which:

FIG. 1 is an exploded view showing the elements of our preferredportable punch;

FIG. 2 is a plan view of our improved portable punch;

FIG. 3 is an elevational view of our punch showing the relationship ofthe punch elements to one another;

FIG. 4 is a side elevational view of the punch shown in FIG. 3; and

FIG. 5 illustrates the sequential steps a through d followed in applyingour punch to form an electrical switch opening in a panel.

Referring to FIGS. l-4, we have shown the elements of our novel portablepanel punch and their relative position to one another. The punchcomprises a die member 10, preferably made of steel. An opening 11 islocated centrally in the die member 10. The opening 11 is shown as arectangular opening, but may be of any desired configuration. As shown,the size of the opening 11 approximates the size of the opening in astandard electrical wall switch panel, with respect to which our punchwill be described. At either end of the central opening 11 and extendingthrough die member 10 is a pair of holes 12, which correspond to screwholes in a standard electrical switch panel (FIG. 5d).

The die member 10 includes sidewalls 13- which run the length of the diemember and are spaced from one another to provide a longitudinal slot 14in the surface of the die member 10. A pair of substantially similarinsert sections 16 and 17, preferably made of tool steel, are adapted tobe inserted in opposed relationship within the longitudinal slot 14 inthe die member 10. A slot 18 is provided in each insert section 16 and17 along an edge thereof. These may be milled in the insert sections.

At either end of the slot =18 along the same edge is a seim-circulargroove 19 which comprises half a hole formed when the insert sections 16and 17 are mated in opposed relation within the longitudinal slot 14 ofthe die member 10. Similarly, the slots 18 of the insert sections 16 and17, when opposed within the slot 14 in the die member 10, provide acentral opening which is aligned with the opening 11 in the die member.

It is to be understood that the opening 11 in the die member may beformed by one of a number of conventional methods. The opening 11 may bemade 'by drilling a series of holes and hand filing to rough dimensionsto a size at least as large as the opening formed by the opposed slots18. The opening 11 may also be broached in the die member 10 accordingto well-known methods.

When positioned within the longitudinal slot 14, the insert sections 16and 17, which may be made of magnetic steel, are secured within the diemember by a plurality of fastening means, such as Allen head screws 20,three of which are shown in FIG. 1. The Allen screws are insertedthrough bores 21 in a sidewall 13 of the die member and are threadedinto abutting relationship with a face 22 of one of the insert sections16 and 17.

A base member 23 comprises two base elements 24 and 25. When joinedtogether, face 26 of the base element 24 and 27 of base element aresubstantially planer and provide a continuous working surface for thebase member 23 (FIG. 4). A slot 28 is provided in element 24. When theelements 24 and 25 are joined together, the slot 28 is substantiallyclosed to form an opening which extends through the base member and issubstantially aligned with the opening formed by the opposed slots 18 ofthe insert sections and the opening 11 in the die member 10. The baseelement 25 is secured to the base element 24 by Allen cap screws, two ofwhich are shown at 25a, which extend through bores 25b in the element 25and are threaded into and engage threaded holes 29 in element 24.

A punch member 34) having a cutting face 31 each corner of whichcomprises a cutting point is secured in the base member 23. Body 32 ofthe punch member 30 is inserted in slot 28 and held in place by the baseelements 24 and 25 which are tightened by Allen cap screws 25a. When thepunch member is properly inserted in the base member, a continuous fiatplaner surface is formed comprising the lower face of base element 25,the bottom of the punch member 30, and the lower face of the baseelement 24.

Preferably, cutting corners of the cutting face 31 of the punch memberare cut at 15 degree angles (FIGS. 3, 4). When the punch is assembledand the die and base members are closed, the walls of the body 32closely complement the opening formed in the mated insert sections 16and 17 by the opposed slots 18. The punch member and the insert formedby insert sections '16 and 17, being comprised of tool steel, may beclosely toleranced by conventional milling or grinding techniques.

The insert sections 16 and 17 and the cutting face 31 of the punchmember 30 are easily removable merely by disassembly of the punchingtool. The cutting face can be re-ground and the sections filed, groundor milled to sharpen them. If wear of the punch member or insertsections is too advanced for repair, any or all of these elements can bereplaced inexpensively and the remaining punch components salvagedinstead of being discarded.

Templates 36 comprises a fiat plate having a central circular aperture37 and a pair of spaced transverse holes 38. The template is used toestablish the location of the panel where the punch is to be made andmay then be used in the punching operation as an element of the punch bypositioning it on the upper surface of the die member 10.

A bolt 39 having a head 40 and a threaded shank 41 is adapted to beinserted through the aperture 37 in the template to extend through theopening 11 in the die member and through the hole formed by the opposedslots 18 when insert sections 16 and =17 are mated in the slot 18 of thedie member 10. The shank 41 of the bolt 39 is threaded to engage athreaded hole 42 which extends through the punch member 30.

A thrust bearing 43 may be placed on the bolt with a face of the thrustbearing being against the lower part of the head 40 of the bolt 39. Itis retained in such position either by a resilient fastener or ring 44pressed onto the shank of the bolt above the threads and adjacent thethrust bearing 43 or by a simple O-ring tightly fitted around the shankof the bolt.

Pins 45 maintains the die member 10 in alignment with the base member23. The pins are secured in the base member 23. A pair of pins are shownextending perpendicularly from the upper surface of the base element 24.The cross section of each pin 45 is such that it will slide through thehole formed by the semi-circular grooves 19 when the insert sections 16and 17 are opposed, through the holes 12 in the die member 10 andthrough the holes 38 in the template 36.

In working near hot conduit boxes, it is important from a safetyviewpoint that both the punch member and pins extend from the samemember, leaving only the base member within the box and forcing thepunched blank outside the box. If such were not the case, the extendingpins and a dropped blank could touch a hot connection and short circuitit through the punch to the operator or complete undesirable circuits.

In FIG. 5, we have outlined the sequence of steps to be followed inusing our punch to forman opening in a panel, such as usually covers anelectrical switch. Step a shows the template 36 laid over a panel P.Holes corresponding to the template aperture 37 and holes 38 are firstdrilled in the panel.

The punch is then positioned on the panel P, as shown in step b. Thebase member holding the punch member 30 is mounted on one face of thepanel by inserting the pins 45 through the smaller holes formed in thepanel. Die member 10 including the insert sections 16 and 17 is nextmounted on the pins in the opposite face of the panel by aligning theholes formed by the oppositely disposed insert grooves 19 with the pinsand pushing the die member 10 toward the panel to engage the pins 45with the holes 12 in the member 10. Finally, template 36 is placed overthe pins 45.

Our punch may be so designed such that maximum metal thickness which canbe punched is determinable at a glance merely by noting the position ofthe pins 45. In this connection, when a panel to be punched is placedbetween the die and base members and the template placed over the pins,the head of each pin must be flush with or extend above the upper faceof the template .(FIGS. 3, 4). If the pins do not so extend, the panelis too thick and either the panel may be damaged in attempting to punchit and/ or the punch may be damaged in operation.

In FIG. 5b, the pins protrude through the template a short distanceindicating that the panel P can be punched.

In step c, bolt 39 has been tightened and the base member 23 has beendrawn toward the head 40 of the bolt. The punch member 30 has beenforced through the panel P into the insert opening formed by slots 18and into the die member 10, and the panel punched. Panel blank 46 hasbeen punched and is retained above the punch member 30 in the opening=11 in the die member 10.

When the punching operation is completed, our tool is removed and thefinish punched panel P appears as shown in step d of FIG. 5.

Our tool is useful on metal, plastic or composition materials providedthey are thin enough to be accommodated between the punch and diemembers and can be shared cleanly without cracking or deterioratingunder loading.

Having described a preferred embodiment of our invention, it will beunderstood that it may otherwise 'be included within the scope of theappended claims.

We claim: a

1. A tool for punching an opening in a panel in alignment with a centralaperture therein between a pair of holes, one on either side of theaperture comprising:

(A) base and die members,

(a) each of said base and die members having a working surface andadapted to close toward and separate from the other and from a surfaceof a panel disposed therebetween;

(b) said die member having a pair of spaced holes corresponding to thepair of holes in the panel and in its working surface an opening largerthan the opening to be punched by the tool and adapted for alignmentwith the central panel aperture;

(c) said base member having a pair of pins extending substantiallynormal to the working surfaces of the die member and slideablyengageable with said spaced holes in the panel and said die member tomaintain alignment between said base and die members during the punchingof the panel;

(B) an insert removeably secured in the working surface of said diemember and having,

(a) a pair of spaced holes corresponding to and adapted for alignmentwith the spaced holes in said panel;

(b) said holes being of sufficient size to slideably engage said pins;

(c) a central opening corresponding substantially to the opening to bepunched in the panel and adapted for alignment with the opening in saiddie member and the central aperture in said panel;

(C) a punch member having a body and a cutting face carried by said basemember and extending substantially parallel to said pins,

(a) the body of said punch member being removeably secured in said basemember between said pins and adapted for alignment with said openings insaid insert and said die member;

(b) the cutting face of said punch member adapted to be forced throughsaid panel into said insert opening and said opening in said die member;

(c) the punch member having a threaded bore extending from its cuttingface through its body and adapted for substantial alignment with theinsert and said die member openings;

(D) a bolt means having a head and a threaded shank for closing againstand separating the working surfaces of the die and base members from thepanel,

(a) the bolt adapted to be extended through the openings in said diemember and in the panel; and

(b) threaded into the bore of the punch member whereby when the bolt istightened the die and base members are drawn together forcing thecutting face of the punch member into cutting engagement with theopening in the insert.

2. A tool as set forth in claim 1 wherein said insert comprises a pairof flat sections which are substantially identical, each of saidsections having an edge characterized by:

(A) a spaced pair of semi-circular grooves extending transverselythrough said insert; and

(B) a central slot cut in the edge between said grooves, said insertbeing formed by joining the sections along said edge, the opposed slotsforming an opening through said insert and the opposed grooves formingthe holes through said insert with which the pins are adapted toslideably engage.

3. A tool as set forth in claim 1 wherein said base member comprises apair of elements:

(A) at least one of said elements being a pin-carrying element andhaving an edge adapted for joining to the other element;

(B) the edge of said one element having a transverse slot formedtherein; and

(C) the other element being adapted to close the slot to provide theopening in said base member.

4. A tool as set forth in claim 1 and wherein a thrust bearing isdisposed on said bolt means adjacent and between said head and said diemember for preventing fatigue of the bolt upon tightening of the punchmember against the panel.

5. A toolas set forth in claim 4 wherein the bearing is held on the boltwith one face of the bearing adjacent the bolt head by a ringsurrounding the bolt shank, a groove cut in the circumference of theshank adjacent the face of the bearing whereby the ring is held on thebolt and the thrust bearing positioned against the head of the bolt bysnapping the ring in the groove.

6. A tool as set forth in claim 1 wherein the working surface of saiddie member includes a longitudinal slot in which the insert is disposed,the depth of the slot being substantially the width of the insert.

7. A tool as set forth in claim 1 wherein said base and die members aresteel material and said punch member and insert are tool steel.

8. A tool as set forth in claim 1 wherein the cutting face of said punchmember is rectangular and each edge is substantially of V-shapedconfiguration with the four corners of the rectangular face being thehighest points on the face.

9. A tool as set forth in claim 8 wherein the lowest point of the longerparallel edges of the cutting face is deeper than the lowest point ofthe shorter edges of the face and the legs of each of the V-shaped edgesextend at an angle of approximately 15 degrees outwardly from saidlowest points.

References Cited UNITED STATES PATENTS 3,074,165 1/1963 Davis 30-3583,255,526 6/1966 Molitor 30-360 3,269,011 8/1966 Herrstrum 30360 FOREIGNPATENTS 851,760 10/1939 France.

ROBERT C. RIORDON, Primary Examiner I. C. PETERS, Assistant Examiner

